This is not a drill, people: Major League Baseball appears to be moving forward with determining the schedule for a potential three-team Wild Card tiebreaker in the American League.

Obviously, this doesn’t mean the A’s, Rays and Indians are definitely headed toward a three-way tie after the rest of the regular season schedule wraps Sunday. But the fact that we’ve gotten this deep into the season with the three-way scenario still on the table is tremendously exciting for those of us who have long been rooting for this as-yet-unrealized tournament before the tournament.

As of this writing, Oakland, Tampa Bay and Cleveland were expected to choose or receive their A, B or C designations for the potential tiebreaker tourney (more on what that means below) either today or Friday, according to an MLB source. So while it’s still going to take a bit of a mathematical miracle to make this happen, we’ve at least graduated from pipe dream to possibility.

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Here are the records and remaining schedules for the three teams involved:

A's: 95-63, at Mariners today through Sunday

Rays: 95-64, off today, at Blue Jays on Friday through Sunday

Indians: 93-65, at White Sox today, at Nationals on Friday through Sunday

What follows is an FAQ to clear up any confusion on how a three-way AL Wild Card tie would be settled and to explain why deciding on an A, B or C designation is actually pretty tortuous, what this all means for the other AL contenders and how the NL could be roped into a similar-but-much-less-complex mess.

• Wild Card Standings

What happens if the A’s, Rays and Indians are all knotted up after Game 162?

Two games would have to be played just to get to the Wild Card Game.

On Monday, Sept. 30, Team A would host Team B. The winner of that game would proceed to the AL Wild Card Game on Wednesday, Oct. 2.

On Tuesday, Oct. 1, the loser of the game between Team A and Team B would travel to face Team C in Team C’s ballpark. The winner of that game would also proceed to the Wild Card Game..

The winner of the Wild Card Game would face the AL’s No. 1 seed in the best-of-five Division Series that begins next Friday, Oct. 4.

Because the A’s won the season series against the other two clubs (4-3 over the Rays, 5-1 over the Indians), they would have first choice of designation. The Rays, who won the season series against the Indians (6-1) would choose second. The Indians would take whatever is left over.

No coin flips necessary!

So the A’s would obviously choose A (with two shots at advancing, the first of which would be at home), right?

At first glance, you would think so. And the A’s choosing A has a nice symmetry to it.

“Two chances, that’s what I would take,” longtime general manager (and current senior advisor to the Brewers) Doug Melvin said. “But I would want to know how many innings the [regular season finale] is going to go on Sunday!”

A-ha! There’s the rub. These designation decisions will be made in advance of the final weekend of the regular season, and the Cardinals and D-backs can attest to the possibility of the occasional 19-inning affair in this wacky sport.

That factor -- and the A’s location -- makes the decision less clear-cut than it might initially appear. Clearly, Option B would have no appeal to them, because who would want to play up to two games on the road? But Option C is interesting, given the pitching and travel parameters in play here.

If the A’s choose Option C, they get to rest on Monday while the Indians and Rays duke it out nearly 3,000 miles across the country. The A’s would only get one bite at the apple, as it were, but they’d have a rested pitching staff to foist upon a jet-lagged team playing in its third city in as many days.

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“If I’m Oakland, I would take C,” former GM and current MLB Network Radio analyst Jim Duquette said. “Yes, it’s the drawback of potentially being one and done. But you’ve already kind of planned for the Wild Card Game one and done anyway. The idea for me is, what’s the best way to win that first game and also have a chance to advance into and beyond the Division Series? If you have to play two games and then the Wild Card game, there’s three games right there. That’s a big lift. Is your goal to just get [to the Wild Card Game] or to go deep into the postseason?”

The Rays’ decision would be similarly complex if the A’s take A (if the A’s take C, then taking Option A is a no-brainer for the Rays). Would you rather travel across the country to Oakland, knowing if you lose you would then travel back across the country to Cleveland for your second chance? Or would you rather just play at home against the Indians (a team you’ve beaten six times in seven tries) on Tuesday and take your chances?

Go deep enough into the mental woods here, and the Indians’ position of just going wherever they’re told actually doesn’t sound so bad.

So the schedule could get a hairy, huh?

Uh, yeah.

Consider a scenario in which the A’s take Option A and the Rays take Option B. If the wins and losses break right, the Rays’ schedule could end up looking like this:

Sunday in Toronto

Monday in Oakland

Tuesday in Cleveland

Wednesday in Oakland again

Or say the A’s take A and the Rays take C. With the right combo of wins and losses, the Indians could wind up with this itinerary:

Sunday in Washington

Monday in Oakland

Tuesday in Tampa Bay

Wednesday in Oakland

We could go on like this, but you get the idea. The inclusion of a West Coast club in this dance makes a complicated scenario even more mentally and physically taxing.

What does this mean for the Astros and Yankees?

It means the incentive to be the No. 1 seed might be stronger than ever.

Granted, if the tiebreaker doesn’t come to be, the Oakland, Tampa Bay and Cleveland pitching staffs are all a load. They are strong enough to overcome burning their best-available starter in the Wild Card Game and remaining a tough draw in the ALDS.

But if the tiebreaker tournament does happen and your ALDS opponent has played at minimum two and possibly three high-stakes games earlier in the week, that makes the No. 1 seed’s edge in rested arms and bodies all the more real.

Right now, the Astros have a big leg up in obtaining that edge. They hold the tiebreaker over the Yankees by virtue of a 4-3 head-to-head advantage in the season series, and they’re up 3 games in the loss column with four to play (three remaining games for the Yankees).

If the three-team tournament does happen, how is home-field advantage in the Wild Card Game decided?

It reverts back to regular season head-to-heads. So the A’s would be the host team if they faced the Rays or Indians. The Rays would host if they played the Indians. The Indians could not host that game in any scenario.

Oh, and if you’re wondering what happens if the A’s choose Option A, lose to the Rays on Monday (making the season series 4-4) and then beat the Indians on Tuesday, they would still have the home-field edge over the Rays on Wednesday. Even though the season series between Oakland and Tampa Bay would technically now be knotted at four wins apiece, the Rays’ Game 163 victory would not count toward the home-field determination.

What about a three-way tie in the NL?

Could still happen! But while a tie involving the Cardinals, Brewers and Nationals would definitely be complicated, it’s actually much more straightforward than what’s on the table in the AL.

Here’s where things stand entering today:

Cardinals (1st in NL Central): 90-69, vs. Cubs on Friday through Sunday

Brewers (2nd in NL Central): 88-70, at Reds today, at Rockies on Friday through Sunday

Nationals: 89-69, vs. Phillies today, vs. Indians on Friday through Sunday

If those three teams wind up tied, the Cardinals and Brewers would have to play a game Monday, Sept. 30. The Cardinals would host that game by virtue of their 10-9 record against the Brew Crew this year. The winner of that game would be the NL Central champion and proceed to face the Braves in the NLDS.

The loser of that game would then proceed to the NL Wild Card Game on Tuesday against the Nationals. Both the Brewers (4-2) and Cards (5-2) have a winning record against the Nats this year, so the loser of the NL Central tiebreaker would host Washington in this scenario. The Game 163 loss and its effect on the NL Central team’s overall season record would not be held against them with regard to the home-field tiebreaker.